body{
    background-image:url("../../img/login-img/avengers.jpg");
    background-size:100% auto;
    background-repeat: no-repeat;
    width: 100%;
    height: 100%;
}

#div{
    position: absolute;
    top: 50%;
    left: 50%;
    -webkit-transform: translate(-50%,-50%);
    -moz-transform: translate(-50%,-50%);
    -ms-transform: translate(-50%,-50%);
    -o-transform: translate(-50%,-50%);
    transform:translate(-50%,-50%) ;
}
